starter.rkt

#lang racket
; Enter your code here. Read input from STDIN. Print output to STDOUT

; Func : None -> None
; Reads a list with variable inputs
(define (func)
  (let ([num (read)])
        (cond
         [(number? num) (cons num (func))]
         [else '()])))

(define arr (func))

; remove-odd : [List-of X] -> [List-of X]
; Removes elements at odd positions
(define (remove-odd arr)
  (local ((define (remove n l)
            (cond
             [(empty? l) '()]
             [(= (modulo n 2) 0) (remove (+ 1 n) (rest l))]
             [else (cons (first l) (remove (+ 1 n) (rest l)))])))
         (remove 0 arr)))

; p: [List-of X] -> Console
; Prints out a list line by line
(define (p l)
  (cond 
   [(empty? l) (printf "")]
   [else (print (first l))
         (printf "\n")
         (p (rest l))]))

(p (remove-odd arr))